function adapt(designWidth, rem2px){
    var d = window.document.createElement('div');
    d.style.width = '1rem';
    d.style.display = "none";
    var head = window.document.getElementsByTagName('head')[0];
    head.appendChild(d);
    var defaultFontSize = parseFloat(window.getComputedStyle(d, null).getPropertyValue('width'));
    // d.remove();
    // document.documentElement.style.fontSize = window.innerWidth / designWidth * rem2px / defaultFontSize * 100 + '%';
    var st = document.createElement('style');
    var portrait = "@media screen and (min-width: "+window.innerWidth+"px ) {html{font-size:"+ ((window.innerWidth/(designWidth/rem2px)/defaultFontSize)*100) +"% !important;}}";
    var landscape = "@media screen and (min-width: "+window.innerHeight+"px ) {html{font-size:"+ ((window.innerHeight/(designWidth/rem2px)/defaultFontSize)*100) +"% !important;}}"
    st.innerHTML = portrait + landscape;
    head.appendChild(st);
    return defaultFontSize
};
var defaultFontSize = adapt(375, 16);